Circular mortise hinge



MMarch 19, 1963 E. L. GUERRANT 3,031,482

CIRCULAR MORTISE HINGE Filed March 31, 1958 /3 FIG. 2.

E DMONDS L. GUERRANT INVENTOR.

ATTORNEY United States Patent Ofifice 3,0S1,482 CIRCULAR MORTISE HINGE Edmonds L. Guerrant, Neil P. Anderson Bldg, Fort Worth, Tex. Filed Mar. 31, 1958, Ser. No. 724,982 3 Claims. (Cl. 16-128) This invention relates to builders hardware and has reference to improvements in door hinges.

While the invention is capable of on the job installation, it is particularly adaptable for use in the manufacture of prefabricated door units, that is, units in which the doors are hingedly mounted intheir frames prior to delivery to the building site. Generally, the invention is directed to a hinge having circular halves or leaves each having a single suitable screw positioned therethrough. Similar hinges have been proposed for use in cabinets where the weight of the doors was not material. Heretofore, cabinet hinges have been made wherein circular leaves and their knuckles were mortised in the outer faces of the hinged parts, and wherein conventional wood screws were employed in the centers of the leaves for holding the hinge in place. However, it is believed to be obvious that such hinges would not be practical for hanging relatively heavy doors, as in houses and buildings, since such doors would have a tendency to sag when opened 90 with reference to their frames. Such sagging, though slight each time the door is opened, would result in slight rotation of each leaf about its screw with the result that the screws would become loose by reason of their frictional engagement with the leaves. The fact that the knuckles may be mortised would not satisfactorily prevent the hinges of heavy doors from oscillating, and would consequently rotate the screws since the material around the mortised knuckles would be of wood and therefore relatively soft. Moreover, such mortising of knuckles would tend to defeat one of the purposes of the present invention, and would not be practical in butt type hinges where the knuckles are offsetwith respect to the outer faces of the door and door frame parts to which the hinges are applied.

An object of the invention is to provide a hinge and screw combination for hanging doors and wherein each leaf of the hinge may be mortised by a single rotary cutting operation without additional routing to accommodate knuckles, corners or leaf configurations other than the single arc of a circle.

A particular object is to provide a combination of hinge and screws for doors wherein the leaves of the hinge are circular and wherein a single suitable screw is received in the center of each leaf.

Another object is to provide a hinge and screw combination wherein a pilot hole for a screw is drilled during the same pass as the mortising operation.

Another object is to provide accurate control over dimensions when applying hinges to doors and door jambs; that is, the invention is adaptable to shop tooling whereby the diameters and depth of mortises and center to center dimensions, between mortises may be accurately controlled.

These and other objects will become apparent from the following description and accompanying drawing, wherein:

FlGURE 1 is an elevational view of a hinge and screw combination in accordance with the invention applied to broken portions of a door and door jamb.

FIGURE 2 is a transverse section and broken plan view showing the screws of the invention and the pilot holes therefor, and illustrating the hinge in its open position.

FIGURE 3 is a broken transverse sectional view of a 3,081,482 Patented Mar. 19, 1963 door, jamb and door facing, and showing the hinge in its closed position.

FIGURE 4 is a broken perspective showing circular mortises and pilot holes for receiving the hinges and screws comprising the invention, and

FIGURE 5 is a side elevational view of a preferred screw for use in combination with the presenthinge.

In the drawing, a hinge in accordance with the invention is secured to the edge of a door 11 and to the face of a door jamb 12 at one side of the stop 13. It is to be understood that two or more such hinges are used when hanging any door. The hinge 10 shown includes a pair of circular halves or leaves 14 each having a single fiat head screw 15 in the diametric center thereof. Adjacent sides of the leaves 14 have interfitting rolled knuckles 16 and 17 to provide a barrel, not numbered, for receiving a hinge pin 18. The upper end of the pin 18 is provided with a head 19, and the lower end of the barrel is provided with a similarly shaped tip 20. It will be noted that the length of the barrel is substantially equal to the diameter of either hinge leaf 14, and that triangular fillets 21 extend from the circumferences of the leaves 14 to provide sufiicient support for the end knuckles 16 and for completing the balanced design of the leaf. It will be noted, particularly in FIGURES l and 4, that the arcuate edges 22 of the leaves 14 extend beyond the corner edges of the door 11 and the door jamb :12, it being understood that such arrangement is for accommodating doors of greater or lesser thickness that the one shown.

The screw 15 includes a tapered flat head 23 and a cylindrical shank or body 24. The thread 25 of each screw 15 has an angle a of 25 to 35 and a sharp outer edge I). The convolutions of the thread 25 do not meet at their root diameter but are spaced to provide flats f substantially equal to onethird to two-thirds of the thread height. The end of the screw body 24 opposite the head 23 is provided with a cylindrical lead 26 outwardly of the end of the thread 25, and which lead is chamfered, as at 27. The described thread has greater gripping area than a conventional wood screw, not shown, and is not, therefore, subject to counter-rotation by reason of frictional engagement with the circular leaves 14 which are subject to slight oscillation when the door 11 is opened and closed.

As shown in FIGURES 2 and 4, pilot holes 28 for the screws 15, and circular mortises 29 for receiving the circular leaves 14, are formed in the door 11 and the jamb 12, such operation being carried out by means of a step drill.

In view of the foregoing, it will be apparent that the present hinge and screw combination lends itself to mass production tooling by reason of the simplified drilling and mortising operations. Since the diameter of each pilot hole 2% is substantially equal to the diameter of the screw body 24, and by reason of the described thread 25 configuration having a sharp outer edge, the threads 25 do not materially mangle the fibers of the wood. In-

stead, the fiber-s are cut and displaced under compression to grip the sides of the threads 25. By reason of the increased thread area described in the foregoing, the screws are firmly secured against counter-rotation.

The invention is not limited to the exemplary construction herein shown and described, but may be made in many ways within the scope of the appended claims.

What is claimed is:

1. Means mounting a passage door in a wall opening in a building, said means comprising at least two butt hinges mounted between a vertical edge of the door and a jamb surface of one side of the wall opening, each hinge being comprised of a pair of circular leaves, interfitting knuckles on sides of said leaves providing a hinge barrel, a pin received within said barrel, a single screw hole through the diametric center of each said leaf, a cylindrical pilot hole in said door and said wall opening opposite each said screw hole, circular mortises around said pilot holes adapted to receive said circular leaves therein, arcuate edges of said leaves adjacent said barrel extending beyond corresponding corner edges of said door and said jarnb surface, a screw received in each said pvilot hole and threadedly engaged in the opposing pilot hole, each said screw having a cylindrical body of substantially the same diameter as the pilot hole in which it is engaged, the convolutions of each said thread being spaced at its root diameter, and the included angle between threads being substantially within the range of 25 to 35 to form a sharp outer edge.

2. Means mounting a passage door in a wall opening in a building as defined in claim 1 and wherein each said References Cited in the file of this patent UNITED STATES PATENTS 174,639 Parsons Mar. 14, 1876 FOREIGN PATENTS 53,391 Switzerland Nov. 29, 1910 OTHER REFERENCES Modern Fabrication (Lescarboura), published in Radio Engineering, November 1931, page 39. 

1. MEANS MOUNTING A PASSAGE DOOR IN A WALL OPENING IN A BUILDING, SAID MEANS COMPRISING AT LEAST TWO BUTT HINGES MOUNTED BETWEEN A VERTICAL EDGE OF THE DOOR AND A JAMB SURFACE OF ONE SIDE OF THE WALL OPENING, EACH HINGE BEING COMPRISED OF A PAIR OF CIRCULAR LEAVES, INTERFITTING KNUCKLES ON SIDES OF SAID LEAVES PROVIDING A HINGE BARREL, A PIN RECEIVED WITHIN SAID BARREL, A SINGLE SCREW HOLE THROUGH THE DIAMETRIC CENTER OF EACH SAID LEAF, A CYLINDRICAL PILOT HOLE IN SAID DOOR AND SAID WALL OPENING OPPOSITE EACH SAID SCREW HOLE, CIRCULAR MORTISES AROUND SAID PILOT HOLES ADAPTED TO RECEIVE SAID CIRCULAR LEAVES THEREIN, ARCUATE EDGES OF SAID LEAVES ADJACENT SAID BARREL EXTENDING BEYOND CORRESPONDING CORNER EDGES OF SAID DOOR AND SAID JAMB SURFACE, A SCREW RECEIVED IN EACH SAID PILOT HOLE AND THREADEDLY ENGAGED IN THE OPPOSING PILOT HOLE, EACH SAID SCREW HAVING A CYLINDRICAL BODY OF SUBSTANTIALLY THE SAME DIAMETER AS THE PILOT HOLE IN WHICH IT IS ENGAGED, THE CONVOLUTIONS OF EACH SAID THREAD BEING SPACED AT ITS ROOT DIAMETER, AND THE INCLUDED ANGLE BETWEEN THREADS BEING SUBSTANTIALLY WITHIN THE RANGE OF 25* TO 35* TO FORM A SHARP OUTER EDGE. 